Electric fluid valve



De.17,196sl H.K.HANEY ETAL 3,416,549

EMEICTRJC FLUIDv VALVE Filed 0G12. 25, 1965 7 Sheets-Sheet l L Min. All.'l N l ,0R/0x? wr 1V ENTORS. #Az me 7.P ,wu/Dean Dec. 17, 1968 H. K.CHANEY ETAL 3,416,549

ELECTRIC FLUID VALVE Filed oct. 25, 1965 lv sheets-sheet e v HZ0 K lAMPA/PIER HZZ 2 AMM/#76E AMPL/F/EE 4 AMPL/F/fe 9 z AMPL #575emvEN'roRs'. #Am/0e 7? ww/awo meow A. aff/wey ELECTRIC FLUID VLVE H. K.CHANEY ET Al.

Dec. 17, 1968 Filed OCt. 23, 1965 Oar p/ l 64 40"0 AMPA Dec. 17, 1968 H.K. cHANEY ET AL 3,416,549

ELECTRIC FLUID VALVE 7 Sheets-Sheet 4 Filed Oct. 23, 1965 5 IWENTORSHAM/0E 7. 5mm/0,900 BY HAMA@ /6 WAHL-V 17, 1968 H. K. cHANx-:Y ET AL3,416,549

ELECTRIC FLUID VALVE Filed 001'.. 23, 1965 7 Sheets-Sheet 5 (mm T 3 IAPDRe/g 55.5 u L HAPLD K. (IMA/EY De.17,1968 H.K.HANEY am. l 3,416,549

ELECTRIC FLUID VALVE Filed Oct. 23, 1965 7 Sheets-Sheet 6 Maw/12D 5 Il',

N57' FOQE Dec. 17, 1968 H. K. CHANEY ET An. 3,416,549

ELECTRIC FLUID VALVE Filed Oct. 25, 1965 7 Sheets-Sheet 7 y gy. lz.

VENTORS.

United States Patent O 3,416,549 ELECTRIC FLUID VALVE Harold K. Chaneyand Halvor T. Strandrud, Seattle, Wash., assignors to The BoeingCompany, Seattle, Wash., a corporation of Delaware Filed Oct. 23, 1965,Ser. No. 503,032 8 Claims. (Cl. 137-815) ABSTRACT OF THE DISCLOSURE Anelectric fluid control apparatus having a plurality of electricallyconducting plates defining an electric fluid passageway therebetween andcircuit means interconnecting said plates with a field control sourcewhereby an electric or magnetic field is established between the platesto control the electric fluid therebetween. The electrically conductingplates are geometrically arranged and proportioned so as to exhibitpressure drops or flows that are related by integral ratios.

This invention relates to means for the control of hydraulic power. Moreparticularly, the invention comp-rises valves which contain no movingparts and use a special hydraulic fluid which responds to anelectrostatic field. Furthermore, the valves are specifically combinedfor direct control by numerical or digital control signals.

Electrically controlled hydraulic fluid valve means exist in the priorart. The basic electrically controlled hydraulic valve element known inthe prior ar-t consists of two electrically conducting surfaces spaced auniform distance apart which form a passageway through which theelectrically sensitive fluid flows, and a source of voltage between theconducting surfaces. The electrically conducting surfaces may be inparallel plane configuration or formed into closed cylinders or othershapes as long as the spacing is maintained essentially constant. Anyopen edges must be closed in order to confine flow of the fluid betweenthe two surfaces.

The properties of fluids which are controllable by an electric ormagnetic field are well known and understood. Such fluids have theproperty of becoming substantially rigid in the presence of a suitableeld. Fluids suitable for the practice of the subject invention may beresponsive to electric or magnetic fields, or both. The formulation ofsuchfluids is exemplified by the patent to Willi-s M. Winslow,2,661,596. The composition of and preparation of such uids does not forma part of this invention. The effect of an applied field manifestsitself as an instantaneous and reversible change in the modulus ofviscosity of the fluids. In strong fields, the liuid undergoes adramatic change in shear resistance, and takes on semiplastic or solidphysical properties. The applied field is magnetic and induced by theaction of electromagnets in the case of magnetic fluids. Where fieldresponsive fluids are used, as is preferred "in this invention, anelectric potential is applied between the adjacent surfaces which boundthe fluid film. Since the fluid-s themselves are dielectric, the currentand power requirements are relatively small.

Prior methods for digital control of hydraulic power have required theuse of mechanical servo valve elements which are more complex,expensive, and considerably slower in operation than the subjectinvention.

An object of the present invention is to provide multiple valve elementshydraulically in series or in parallel, having separate electricalcontrol leads.

3,416,549 Patented Dec. 17, 1968 Another object of the present inventionis to provide a group of valve elements so proportioned as to exhibitpressure drops that are related by integral ratios, or flows that arerelated by integral ratios.

A further object of the present invention is the control of anassemblage of valves by a group of signals representing discretenumerical values.

The invention is best described with reference to the drawings in which:

FIGURE l is a schematic representation of the basic electricallycontrolled hydraulic valve element well known in the prior art.

FIGURE 2 is a schematic representation of a valve for the control ofhydraulic power according to the teachings of thi-s invention.

FIGURE 3 is another schematic representation of a valve for the controlof hydraulic power according to the teachings of this invention.

FIGURE4 is still another schematic representation of a valve for thecontrol `of hydraulic power according to the teachings of thisinvention.

FIGURE 5 is a furthe-r schematic representation of a valve for thecontrol of hydraulic power according to the teachings of this invention.

FIGURE 6 is another schematic representation of a valve for the controlof hydraulic power according to the teachings of this invention.

FIGURE 7 is a schematic representation of a valve for the control ofhydraulic power according to the teachings of this invention.

FIGURE 8 is a seventh schematic representation of a valve for the-control of hydraulic power laccording to the teachings of thisinvention.

FIGURE 9 is still another schematic representation of a valve for thecontrol of hydraulic power according to the teachings of this invention.

FIGURE l0 is an isometric view of a valve for the control of hydraulicpower according to the teachings of this invention.

FIGURE 11 is a schematic representation of an electric fluid actuatorincorporating a valve arrangement according to the teachings of thisinvention.

FIGURE 12 is a schematic representation of an electric fluid actuatorincorporating two valves according to the teachings of this invention.

FIGURE 13 is a second embodiment of the schematic representation shownin FIGURE 11.

FIGURE 14 is a schematic representation of an electric fiuid actuatorwherein multiple valves are used according to the teachings of thisinvention.

Basic relationships relating fiow and pressure drop which are pertinentto the teachings of this invention are summarized with reference toFIGURE 1. For a given fluid ow, for example, Q gallons per minute,pressure drop P: (a) increases in direct proportion to length of valveL; (b) decreases when the width of valve W increases; (c) decreases whenthickness D increases; and (d) increases when control voltage Eincreases.

The basic principles of the numerically controlled hydraulic valveaccording to the teachings of the instant invention are illustrated bythe pressure control valve assembly shown in FIGURE 2. Electricallysensitive fiuid is caused to fiow at some constant rate, for example, Qgallons per minute, through a valve means which unlike the valve ofFIGURE l consists of a number of valves which are hydraulically combinedin series. Although four valves are shown here for purposes ofillustration, any

number can be used, depending upon the specific requirements; the iiuidflows between parallel surfaces of what appears to the fiuid as twoparallel members or plates having closed edges to confine the flow ofthe fluid. It is to be noted, however, that the instant invention is notrestricted to valves formed by parallel plates; on the contrary, thevalves may comprise individual cylindrical shells disposed in parallelconcentric fashion. The embodiments of FIGURES 2 through 9 can, thoughdiscussed in terms of parallel plates, be thought of as elementalportions of cylindrical shells.

Continuing with reference to FIGURE 2, plate 10, which is electricallygrounded, is a conducting member or plate that is common to the fourvalves. The other electrically conducting members or plates for the fourvalves are plates, 12, 14, 16 and 18, which are of uniform Width W andwhich are uniformly spaced distance D from plate 10, but which havelengths in the direction of fluid ilow in the ratios l:2:4:8 as shown.Plates 12, 14, 16 and 18 are insulated from each other and from plate 10by suitable insulation 17; plates 12, 14, 16 and 18 with plate are soarranged as to form a smooth, continuous passageway for the uid to flowthrough.

Plates 12, 14, 16 and 18 are energized through arnpliers 20, 22, 24 and26, respectively, from lines carrying parallel binary control signalswhich represent vales 1, 2, 4 and 8, respectively, when energized from abinary potential control signal source 3. Depending upon the presence orabsence of a control signal on each of the lines carrying parallelbinary control signals, either zero volts or some selected voltage Ewill be applied by the amplifiers 20, 22, 24, and 26 to the respectiveplates 12, 14, 16, or 18. When zero voltage is applied to any one of theplates, pressure drop across the plate will be small and may beneglected. When some value of voltage E is applied to one or more ofplates 12, 14, 16, or 18, pressure drops across the energized plateswill be in proportion to plate lengths and will therefore be in the samenumerical ratios as the integers representing the energized controllines from amplifiers 20, 22, 24, and 26 to plates 12, 14, 16, and 18,respectively. Total pressure drop across the entire valve assemblage ofFIGURE 2 is the sum of the pressure drops across the individual valves.Thus, for example, if the control lines energizing plates 12, 14, and 18are energized simultaneously, the total press-ure drop across the valveassemblage will be P1+2P1+8P1=11P1- In general, the total pressure dropwill be in proportion to whatever number is represented by the inputbinary control signals from the signal source 3 to amplifiers 20, 22,24, and 26.

Use of a binary numbering system for control signals is not essential tothe operation of this invention. Input signals can represent any desirednumbers depending upon the particular application. Lengths of the plates12, 14, 16, and 18 would be in proportion to the numbers represented byin-put signals. Likewise, with reference to the embodiment of FIGURE 2,use of amplifiers 20, 22, 24, and 26 is not essential; the amplifiersmay be dispensed with if the control signal lines are capable ofsupplying sufiicient power. Additionally, numerical control is achievedby proper proportioning of the lengths of individual valves making upthe assemblage. However, as will be seen with reference to FIGURES 3, 4,and 5, any of the other parameters (D, W and E, as seen in FIGURE l)relating fluid flow, Q, to pressure drop, P, may be made the basis forproportioning the several valves making up a numerically controlledassemblage. In addition, any combination of these parameters may beused.

With reference to FIGURE 3, a valve assemblage according to theteachings of this invention is disclosed for the numerical control ofpressure in which spacing, D, is varied for the individual valves butparameters, L, W, and E, are the same for all valves. Here members orelectrically conducting plates 28, 30, 32, and 34 are of uniform length,L, insulated from one another by insulation 17, but are spaced variousdistances as shown from grounded plate 36 and separated from plate 36 byinsulation 17 such that their pressure drops are related in the ratios1:2:4:8, respectively. The numerical control of pressure by input binarysignals from a source 3 is accomplished by energizing desiredcombinations of numerical input lines in the same manner as describedabove in the embodiment of FIGURE 2.

FIGURE 4 shows a valve assemblage according to the teachings of thisinvention for a numerical control of pressure in which width, W, isvaried for the individual valves, and parameters D, L, and E are thesame for all valves. Here members or electrically conducting plates 38,40, 42, and 44 are of varying width, W1, W2, W3 and W4, and are spacedan equal distance, D, from grounded plate 46 and are insulated from oneanother and from plate 46 by insulation 17. The average widths of thevarious plates are proportioned to produce pressure drops across plates38, 40, 42 and 44 in the ratios 1:22418, respectively. The numericalcontrol of pressure is accomplished by energizing desired combinationsof numerical input lines in the same manner as described above for theconfiguration shown in FIGURE 2.

In the configuration shown in FIGURE 5, the individual valvesrepresented by electrically conducting members or plates 48, 50, 52, andS4, insulated from one another by insulation 17, have identicaldimensions L and W and are equally spaced a distance D from electricallyconducting plate 56 and insulated from plate 56 by insulation 17. Inthis embodiment, however, the outputs of the amplifiers 20, 22, 24, and26 are so adjusted as to produce different output voltage,s E1, E2, E3,and E4, respectively. Voltages E1, E2, E3, and E4 are selectivleyproduced by said amplifiers to produce pressure drops in the valves 48,50, 52, and 54 in the ratios 1:2:4:8, respectively, when input signalsare applied to said amplifiers from a binary control source 3. A totalpressure drop in proportion to the numerical input is thus realizable inthe same manner as described above by energizing desired combinations ofthe numerical input lines connecting the plates 48, 50, 52, and 54 withamplifiers 20, 22, 24, and 26, respectively.

The embodiments described above with reference to FIGURES 2 through 5produce a numerically controlled pressure drop through the valve in thedirection of flow at a constant ow rate Q. Described below in FIGURES 6through 9 are embodiments which produce a numerically controlled flow Qwhen constant pressure is applied. The basic principles discussed aboveare involved and are similar except that for ow control using theembodiments of FIGURES 6 through 9 the individual valves arehydraulically in parallel instead of in series as is the case withreference to the embodiments of FIGURES 2 through 5.

FIGURE 6 shows a valve assemblage for the numerical control of flow Q inwhich four separate valves are shown for illustration, although anydesired number can be used to meet specific requirements. By means ofsuitable ducts or manifolds (not shown), electrically sensitive uid isled to the top of the embodiment of FIGURE 6 (as shown) and is collectedfrom the several valves and led away from the bottom of the embodimentof FIGURE 6 as shown. A constant pressure P p.s.i. is maintained acrossthe embodiment as shown.

Continuing with reference to FIGURE 6, one electrically cnoductingmember or plate of each of the valves 58, 60, 62 and 64 is at ground.The ungrounded plate of each of the valves 58, 60, 62 and 64 isconnected to an amplifier 20, 22, 24 and 26, respectively. Whereappropriate, each of said plates at ground are insulated from each ofsaid plates connected to an amplifier by any suitable insulating means66. Each of said amplifiers is energized from one of a set of numericalcontrol lines from a binary potential control signal source 3. Here thepresence of a voltage on any one of the numerical control lines 8, 4, 2,or 1 represents a zero for that particular line;

absence tof a voltage represents a digit 8, 4, 2, or 1, respectively, aswill be explained below.

All of the valves of FIGURE 6 have the same plate width W and the sameplate spacing D as shown. Lengths L4, L3, L2 and L1 are so chosen thatwhen the valves 58, 60, 62 and 64 are de-energized, the quantity offiuid flow through the valves will be in the proportions8Q1:4Q1:2Q1:1Q1, respectively. Qutput voltages E4, E3, E2 and El of theamplifiers 20, 22, 24 and 26, respectively, are sufficient toeffectively stop the flow Q of fluid in the respective valves 58, 60, 62and 64 when the individual associated control lines are energized. Thus,for example, absence of a signal on control line 8 (the control lineleading to amplifier 20) results in zero output voltage from amplifier20 and allows a flow of 8Q1 through valve 58, as shown in FIGURE 6.Total flow through the assemblage will thus be in proportion to the sumof the integers represented by the de-energized control signal lines 8,4, 2 and 1.

As in the case of the digital pressure control configurations, FIGURES3, 4 and 5, digital flow control valves can be built based on varyingthickness D, varying width W, and varying voltage E, or any combinationof these parameters.

FIGURE 7 shows a numerical flow control valve assemblage in which theindividual component valves 68, 70, 72 and 74 have different member orplate spacings, D4, D3, D2 and D1, respectively. Electrical controlmeans are the same in FIGURE 7 as in FIGURE `6. In the embodiment lofFIGURE 7, insulating means 66 are again used as shown. In the embodimentof FIGURE 7, pressure drop P does not vary and the length L and Width Wof the individual valves are equal.

The distances D4, D3, D2 and D1 are so chosen that when the valves 68,70, 72 and 74 are de-energized, the quantity of fluid `flow Q will be inthe proportion S14-:211, as shown, respectively. Output voltages E4, E3,E2 and E1 imposed upon each of the valves 68, 70, 72 and 74 byamplifiers 20, 22, 24 and 26, respectively, as was the case withreference to FIGURE 6, are sufficient to effectively stop the flow ofuid in the respective valves when the individual associated controllines 8, 4, 2, and 1 are energized. Thus, for example, absence of asignal to valve 68 results in zero output voltage from the amplifier 20associated with valve 68 as in FIGURE 6 and allows a flow of 8Q1 throughvalve 68 as shown in FIGURE 7. Presence of a signal on control line 8will result in zero iiow through valve 68. Total flow through the valveassemblage of FIGURE 7 will thus be in proportion to the sum of theintegers represented by the de-energized control signal lines.

In FIGURE 8, the Width W varies for individual valves while length L andspacing D are uniform. Insulation means 66 is disposed as in FIGURES 6and 7 and again electrical control arrangements are the same as in FIG-URE 6. Pressure drop P and fluid flow Q in gallons per minute throughvalves 76, 78, 80 and 82 are effected in the same proportions as was thecase with reference to FIGURES 6 and 7.

In the arrangement shown in FIGURE 9, the valves 84, 86, 88 and 90 ofthe assemblage as shown have the same dimensions length L, width W, andare uniformly spaced by an amount D. Presence of a signal on one of thenumerical input lines 8, 4, 2 and/ or 1 from binary potential controlsignal source 3 produces a voltage E4, E3, E2 and/or E1, respectivley,which stops flow of uid in the respective valve. As shown in FIGURE 9,output voltage E41, E31, E21 and E11, respectively, are so proportionedas top roduce flows 8Q1, 4Q3, 2Q1 and Q1, respectively, through therespective individual valves 84, 86, 88 and 90. Output voltages E4, E3,E2 and E1, respectively, produce zero ow through the respectiveindividual valves 84, 86, 88 and 90.

In each of the above embodiments, FIGURES 2 through 9, only oneparameter L, D, W, or E is varied in each figure for simplicity ofexplanation. This restriction is not essential to the operation of thisinvention. In a valve assemblage for the numerical lcontrol of pressure,any or all of the parameters, L, D, W or E may be varied from one valveto another, as long as the pressure drop across each valve (whenenergized) is in proportion to the numerical value of the associatedcontrol line. Similarly, in a valve assemblage for the numerical controlof flow, any or all of the parameters L, D, W or E may be varied fromone valve to another as long as the flow through each valve (whende-energized) is in proportion to the numerical value of the associatedcontrol line.

In the arrangement shown in FIGURE l0, a plurality of members, viz.,cylindrical shells 91, are nested parallel to and concentrically aboutone another between an output shaft 89 and a casing 93 to form a groupof parallel gaps 87 having uniform spacing. The shells 9.1 are supported(by means not shown) in such manner as suitable for a particularembodiment, e.g., within and to casing 93 thereby being prevented fromaxial or radial displacement, or within casing 93 but attached to shaft89 so as to reciprocate with shaft 89 and operate as a piston. A controlvoltage E (which can be regulated by a control source 3) is applied byleads 85a to alternate shells 91. The other shells 91 are electricallyplaced at a different and uniform potential (e.g., ground) through leadsb, as are shaft 89 and casing 93. A field is thus established acrosseach of the gaps 87 whenever a voltage E is present in leads 85a. As thefield is established, fluid flow through gaps 87 is prevented; the forceof the fluid against shaft 89, and, when shells 91 are attached to shaft89, against the piston formed by shells 91 will thus provide an axialdisplacement of shaft 89; i.e., an output. Removal of the field againallows flow through gaps 87, thus allowing shaft 89 to return toequilibrium as will be discussed more fully below.

With reference to FIGURES l1 through 14, various practical applicationsof the valves as considered in FIG- URES 2 through 10 are disposed foroperation. It is to be understood that the embodiments represented inFIG- URES ll through 14 are illustrations or applications in anon-limiting sense. More particularly, the valves in FIGURES 11 through14 comprise individual members or cylindrical shells disposed inparallel concentric fashion and having uniform spacing betweenindividual shells, each shell being of uniform length L with respect toeach other concentric shell. For purposes of illustration, there are noamplifiers or numerically controlled variations in energizing voltage Eas was the case in FIGURES 2 through 9; on the contrary, a singlevoltage E is used for purposes of illustration, as was the case in theembodiment of FIGURE l0. Numerical controlled variations of voltage Ecan be used where desired, however, according to the teachings of thisinvention.

Referring to FIGURE l1, a single valve electric fluid actuator is shownschematically and in cross section. The embodiments shown in FIGURES 11through 14 provide applications utilizing the electric field sensitivehydraulic fluid to produce an output force related to input electricalsignals. With particular reference to the embodiment of FIGURE ll, theactuator has many desirable characteristics: it is small in size, hasfew parts, and is extremely lightweight. In particular, the Weight ofthe moving parts can be made relatively light to increase theperformance capability of the embodiment in applications where fastresponse is needed (for example, high speed automatic control). Further,no electric power is required by the moving parts, thus eliminating theneed for moving contacts or flexible wiring to the Inoving parts. Thepiston and rod assembly is more rigid (as well as lighter), facilitatingthe elimination of undesirable mechanical resonances to thereby increasethe useful range of operating frequencies. Still further, an advantageresides in the reduction of electric power requirements 'i needed toprovide operation of the embodiment application described with referenceto FIGURE 1l.

The subject device combines valve and actuator functions into oneassembly as shown in FIGURE ll. A cylindrical housing 92 of anyconvenient rigid material provides a pressurized container for theelectric fiuid (not shown). Mounted within housing 92 and attached tothe housing by any suitable mechanical means (not shown) is a valve 94comprising a group of members or cylinders 95 disposed in parallelconcentric relationship and uniformly spaced and electrically insulated(by means not shown) from one another. Alternate cylinders 95 areconnected to an electric power lead 96; the remaining cylinders 95 areat ground.

Mounted within housing 92 and disposed to reciprocate axially is anassemblage comprising a member or piston 98 rigidly mounted on a memberor output shaft 100. Seals (not shown) are provided to prevent fiuidleakage between piston 98 and housing 92, and to prevent fluid leakagewhere output shaft 100 passes through the ends of housing 92. Connectedbetween exhaust pressure chamber 102 and chamber 104 is a constant flowtype pump 106 which circulates the electric fiuid at a constant fiowrate through valve 94. When voltage on electric power lead 96 is zero,pressure drop across valve 94 is small, and negligible pressure isexerted against the lower face of piston 98. When a voltage is appliedto lead 96, the resulting voltage gradient between cylinders 95 of valve94 impedes the fluid flow through valve 94. Since the fiow of pump 106is constant, pressure then builds within chamber 104 exerting an upwardforce upon piston 98.

A constant pressure pump 108 maintains a constant pressure betweenexhaust chamber 102 and chamber 110, producing a constant downward forceupon piston 98. Pump 108 is so constructed (by basic design, includingan accumulator, a suitable spring loaded check valve, etc., the detailsof which are not shown) as to allow fiuid flow in either direction,while maintaining constant pressure in chamber .110. Either upward ordownward net force is produced upon piston 98 by applying suitablevoltages to electric power lead 96. When pressure in chamber 104 exceedspressure in chamber 110, the net force is upward; when pressure inchamber 104 is lower than pressure in chamber 110, the net force isdownward. Bi-.directional motion of piston 98 is thus controlled byapplying a suitable voltage wave shape to lead 96. Voltages of any waveshape may be used which elfect the desired result. A reservoir 107provides a storage and continuous source of fluid to be pumped by pumps106 and 108.

Action of the embodiment as shown in FIGURE l1 is not dependent upon theparticular cylinder otr plate 95 configuration described with referenceto the valve 94. Any configuration may be used which provides suitableow spaces across which control voltages can be applied; for example, theembodiments described in FIGURES 2 through l of this invention.

A feature of this invention is provision of an approximately constantdownward force upon the piston 98. Various alternate methods may be usedto provide the constant force as described below: (l) separatereservoirs may be used for pumps 106 and 108 which would permit use ofstandard hydraulic uid in pump 108 instead of the more costly electricfield sensitive fluid; (2) pump 108 may be eliminated and constantpressure maintained in chamber 110 by connecting a charged hydraulicaccumulator (not shown) to the chamber 110; use of standard hydraulicfiuid or of electrically sensitive hydraulic fluid in pressure chamber110 is optional in such a configuration; (3) pump 108 may be eliminatedand chamber 110 may be pressurized by means of a suitable pressurereducer (not shown) connected to the output of pump 106, either with orwithout an associated hydraulic accumulator (not shown) at chamber 110;(4) fiuid pressure may `be omitted from chamber and the constantdownward force on the piston 98 may be obtained through use of asuitable spring (not shown); (5) chamber 110 may be omitted and thepiston replaced by flexible bellows (not shown) which would be attachedto the housing 92 and to the output shaft 100. The bellows would servethe multiple functions of sealing the end of housing 92, developing aforce from the pressure in chamber 104 and transmitting the force to theoutput shaft 100 and providing the required constant downward force onoutput shaft 100.

Each of these variations which could be made on the embodiment of FIGURE1l has its own area of application. For example, if long stroke isrequired, the embodiment of FIGURE 11 itself and alternate l areadvantageous; for short stroke and simplest construction, alternates 4and 5 are advantageous; and where the volume of electrically sensitivefiuid must be minimized, alternates l, 2, 4, or 5 are advantageous.

Referring to FIGURE 12, a two valve electric fiuid actuator is shownschematically and in cross section according to the teachings of thisinvention. The device combines valve and actuator functions into oneassembly as shown. A cylindrical housing 114 provides a pressurizedcontainer for the electric fiuid. The housing is conveniently made ofany strong rigid material. Mounted within housing 114 and attached tothe housing are valves 116 and 118, each consisting of a group ofcylinders 115 with adjacent cylinders spaced and electrically insulated(by means not shown) from one another. Alternate cylinders 115 of valve116 are connected to lead 117, and alternate cylinders 115 of valve 118are connected to electrical lead 119. All valve cylinders 115 notconnected to either voltage supply lead 117 or 119 are connected toground (by means not shown).

Mounted inside housing 114 and disposed to reciprocate axially is anassemblage consisting of a member or piston 120 rigidly mounted on amember or output shaft 122. Seals (not shown) are provided to preventleakage of fiuid between piston 120, housing 114, and to prevent fluidleakage where output shaft 122 passes through the ends of housing 114.

Connected to housing 114 are fluid inlet lines 124 and 126 which receivefiuid from pumps 125 and 127, respectively; and fiuid exhaust lines 128and 130 through which fluid returns to the respective pumps. Thepressure equalizing line 132 equalizes pressures in the chambers at thetwo ends of housing 114. Pumps and 127 are of the fixed displacementtype, delivering constant flow.

Pump 125 circulates fiuid through valve 116 at a constant rate. Whenvoltage at lead 117 is zero, pressure drop across valve 116 is small,and negligible pressure is exerted against the left face of piston 120.When a voltage is applied at lead 117 the resulting voltage gradientbetween valve cylinders 115 of valve 116 impedes the fluid flowtherethrough. Since the pump ow is constant, pressure then builds up inthe chamber at the left of piston 120 as shown, driving the piston tothe right as shown. Similarly, application of voltage to lead 119produces a pressure in the chamber at the right of piston 120 as shown,driving the piston 120 to the left as shown. Motion of piston 120 isthereby controlled by applying suitable voltage wave shapes to leads 117and 119. Voltages of any wave shape and amplitude may be used as long asthey are of sutiicient magnitude to effect the desired result.

Action of the device as shown in FIGURE l2 is not dependent on theparticular cylinder 115 configuration described for valve 116 and 118.Any configuration may be used which provides suitable flow spaces acrosswhich the control voltage through leads 117 and/or 119 can be applied.

FIGURE 13 represents a second configuration of a two valve electricfluid actuator according to the teachings of this invention. FIGURE 13discloses a configuration of a fluid actuator having the advantage ofrequiring only a single pump. Housing 134 is a cylindrical pressuretight container comprising any suitable rigid material which is dividedinto two parts by a member or bulkhead 136. A member or output shaft 138is disposed to reciprocate axially, and is provided with seals (notshown) to prevent liuid leakage at the ends of housing 134 and at thebulkhead 136.

Attached to shaft 138 are valves 140' and 142, each consisting of agroup of cylinders 141 each of which are uniformly spaced from oneanother and electrically insulated (by means not shown) from oneanother. Alternate cylinders 141 of valve 140 are connected to a voltagesource lead 144, and alternate cylinders 141 of valve 142 are connectedto voltage source lead 146. All valve cylinders 141 not so connected toeither of the voltage supply leads are connected to ground.

A pump 148, a fixed displacement pump, circulates electric uid (notshown) at a constant rate of flow through connecting tubing 150 andthrough the actuator chambers and valves as shown by the arrows ofFIGURE 13. The essential feature of this arrangement is that the fluidflows from right to left as shown by arrows through valve 140, and fromleft to right as shown through valve 142. A reservoir 152 maintains aconstant fluid supply at pump 148.

When the potential supplied by leads 144 and 146 equals zero, thepressure drop across valves 140 and 142 is small, and anegligible forceis transmitted to the output shaft 138. If a voltage is applied to lead1-44, the resulting voltage gradient between the cylinders 141 of valve140 impedes the `flow of fluid through valve 140, producing a forcetowards the left on output shaft 138 as shown. Similarly, application ofa voltage to lead 146 impedes the `flow of fluid from left to rightthrough valve 142 as shown and produces a force towards the right onoutput shaft 138 as shown.

Motion of output shaft 138 is thus controlled by applying suitablevoltage wave shapes to leads 144 and 146. Voltages of any wave shape andamplitude may be used so long as they are of sufficient magnitude toeffect the desired result. Action of the embodiment of FIGURE l2 is notdependent upon the cylinder 141 configuration described for valves 140and 142. Any configuration may be used which provides suitable flowspaces across which the control voltage can be applied as, for example,the valves of FIGURES 2 through 9.

Referring to FIGURE 14, the group of cylinders 149 which form valves150, 152, 154 and 156 are insulated (by means not shown) and spaced onefrom the other. Fl-uid flows axially through the spaces and whenadjacent cylinders 149 are given a potential across them, an electricfield is formed in the space and applied to the fluid. The electric eldreduces or stops the fluid flow (a valving action) and the valves 154and 156 then act as a piston to apply any developed force and motion tothe member or output shaft 158. The four groups of cylinders 149 formthe valves 150, 152, 154 and 156 and, in effect, a member or pistondisposed to transmit a force to shaft 158. Valves 150 and 152 areattached to a housing 157, and valves 154 and 156 are attached to theoutput shaft 158 which is disposed for reciprocal axial motion. Theoutput shaft 158 and attached valves 154 and 156 are the only movableparts in the assembly. Electrical connections to the valves 150, 152,154 and 156 are made through terminals 158, 160, 162 and 164.

Operation of the electric uid actuator of FIGURE 14 is as follows.Electric fluid flows into the housing 157 through a port 159, passesthrough the valves 156 and 152 and-'exits through a port 161. Electricfluid also ows into the housing 157 through the port 159, and passesthrough valves 154 and 150 and exits through port 163. When a voltage isapplied to valves 150 and 156 so that no fluid will flow through them,Valve 156 which is attached to output shaft 158 will be subjected tosupply pressure and uid flow from port 159 thus producing a force on theoutput shaft 158 to move it to the right as shown in FIGURE 14. No fluidescapes from port 163 because valve has been energized and therebyclosed. As the output shaft 158 and valve piston 156 move, the displacedfluid moves freely through valve 152 and exhaust port 161. To producemotion and force in the opposite direction, the voltage is removed fromvalves 150 and 156 and applied to valves 154 and 152. Valve 154, nowclosed, acts as a piston on output shaft 158 and the force developedv bythe supply pressure will move the output shaft 158 to the left as shownin FIGURE 14. By the application of DC and/or AC control voltages to thetwo sets of valves 150, 156 and 154, 152 alternately or in combination,the embodiment can be controlled as a function of its position, velocityor force, or related combinations. Voltage of any wave shape andamplitude may be used so long as they are of sufficient magnitude toeffect the desired result.

Voltage is applied to valves 150 and 152 by means of fixed`- electrodes158 and 164 and to valves 154 and 156 by means of electrodes (slidingcontacts) 160 and 162, respectively. Operation is not restricted to thismethod of voltage application nor does it depend upon this method. Anysuitable method may be used to apply voltages to the valves and is notrestricted to the fixed electrodes on valves 150 and 152, nor thesliding contacts 160, 162 on valves 154 and 156, respectively.

The valves of the electric fluid actuator of FIGURE 14 may be made ofmembers such as cylinders or plates according to the teachings of theembodiments in FIG- URES 2 through 10 and may be arranged in anyconfiguration which permits the fluid through the elements either in thepath indicated in FIGURE 14 or the reverse direction of this flow.

Since numerous changes may be made in the above apparatus, and differentembodiments may be made without departing from the spirit thereof, it isintended that all matter contained in the foregoing descriptionreferring to apparatus or shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

We claim:

1. Means in combination foi controlling the pressure drop of a fluid, inthe presence of a field, passing through o said means comprising:

(a) a first electrically conducting plate of Width W;

(b) a plurality of electrically conducting plates of width W, uniformlyspaced a distance D from said first electrically conducting plate ofwidth W and whose lengths in the direction of fluid flow increase in apredetermined ratio;

(c) means to prevent electrical contact vbetween said first electricallyconducting plate of width W and said plurality of electricallyconducting plates of width W and any two of said plurality ofelectrically conducting plates of width W; and

I(d) circuit means for interconnecting a field control source and saidplurality of electrically conducting plates of width W so as toestablish the field between said first electrically conducting plate ofwidth W and said plurality of electrically conducting plates of width Wwhereby yupon energization of said plurality of electrically conductingplates of width W the pressure `drop in the direction of fluid flowthrough said first mentioned means increases in a predetermined ratio.

2. .Means in combination for controlling the pressure drop of a fluid,in the presence of a field, passing through said means comprising:

(a) a first electrically conducting plate of Width W;

(b) a plurality of electrically conducting plates of width W, length L,and each of said plurality of electrically conducting plates beingdisposed substantially parallel to and at a predetermined and 1 1different distance from said first electrically conducting plate ofwidth W;

(c) means to prevent electrical contact between said first electricallyconducting plate of width W and said plurality of electricallyconducting plates of width W and any two of said plurality ofelectrically conducting plates of width W; and

(d) circuit means for interconnecting a field control source and saidplurality of electrically conducting plates of width W so as toestablish the field between said first electrically conducting plate ofwidth W and said plurality of electrically conducting plates of width Wwhereby upon energization of said plurality of electrically conductingplates of width W the pressure drop in the direction of fluid flowthrough said first mentioned means increases in a predetermined ratio.

3. Means in combination for controlling7 the pressure drop of a fluid,in the presence of a field, passing through said means comprising:

(a) a first electrically conducting plate of non-uniform width;

(b) a plurality of electrically conducting plates of length L,non-uniform width, and disposed substantially parallel to and at apredetermined distance D from said first electrically conducting plateand wherein the average widths of said plurality of electricallyconducting plates of length L and non-uniform width in the direction offluid flow vary in a predetermined ratio substantially the same as theaverage width of said first electrically conducting plate of non-uniformwidth;

(c) means to prevent electrical contact between said first electricallyconducting plate of non-uniform width and said plurality of electricallyconducting plates of length L and non-uniform width and any two of saidlatter plates; and

(d) circuit means for interconnecting a field control source and saidlatter plates so as to establish the field between said latter platesand said first electrically conducting plate of non-uniform widthwhereby upon energization of said plurality of electrically conductingplates of length L and non-uniform width the pressure drop in thedirection of fluid flow through said first mentioned means increases ina predetermined ratio.

4. Means in combination for controlling the pressure drop of a fluid, inthe presence of a field, passing through said means comprising:

(a) a first electrically conducting plate of width W;

(b) a plurality of electrically conducting plates of width W, length L,substantially parallel to and uniformly spaced a distance D from saidelectrically conducting plate of width W;

(c) means to prevent electrical contact between said latter plates andsaid first electrically conducting plate of width W and any two of saidplurality of electrically conducting plates of width W and length L; and

(d) circuit means including a plurality of amplifiers forinterconnecting a field control source and said plurality ofelectrically conducting plates of length L and width W whereby voltagesare `selectively produced by said amplifiers to establish the fieldbetween said first electrically conducting plate of width W and saidplurality of electrically conducting plates of width W and length L toproduce pressure drops in the direction of fluid flow in a predeterminedratio.

5. Means for controlling the flow of a fluid in the presence of a field,the combination comprising: a plurality of `valves through which thefluid flows at a constant pressure disposed in substantially parallelrelationship and having non-uniform lengths in the direction of fluidflow, each of said plurality of valves being insulated from one anotherby electrically insulating means and comprising:

(a) a first electrically conducting plate of width W and uniformlyspaced a distance D from (b) a `second electrically conducting plate ofwidth W, each of said plurality of valves being connected to a fieldcontrol source by circuit means so as to establish the field across saidvalves such that upon selective de-energization of all of said pluralityof valves by Isaid field control source, the quantity of flow throughsaid plurality of valves will be in a predetermined proportion and uponselective energization of any one of said plurality of valves thequantity of ,flow through said any one of said plurality of valves willbe zero.

6. Means for controlling the fiow of a fluid in the presence of a field,the combination comprising: a plurality of valves through which thefluid flows at constant pressure disposed in substantially parallelrelationship, and each of said plurality of valves being insulated fromone another by electrical insulating means and comprising:

(a) a first electrically conducting plate of width W and length L;

(b) a second electrically conducting plate of width W, length L,disposed parallel to said first electrically conducting plate andconnected by circuit means to a field control source so as to establishthe field across said valves;

(c) in each of said plurality of valves, each first electricallyconducting plate being spaced a predetermined distance from each secondelectrically conducting plate, the latter distance being different ineach of said plurality of valves, such that upon selectivede-energization of all of said plurality of valves by said field controlsource, the quantity of flow through said plurality of valves will be ina predetermined proportion, and upon selective energization of any oneof said plurality of valves7 the quantity of ow through said any one ofsaid plurality of valve-s will be Zero.

7. Means for controlling the flow of a fluid in the presence of a field,the combination comprising: a plurality of valves through which thefluid flows at a constant pressure disposed in substantially parallelrelationship, each of said plurality of valves having a different width,each of said plurality of valves being insulated from one another byelectrical insulating means and comprising:

(a) a first electrically conducting plate of length L, predeterminedwidth, and uniformly spaced a distance D from and disposed parallel to;

(b) a second electrically conducting plate of length L and predeterminedwidth, which is connected to a field control source by circuit means soas to establish the field across said plurality of valves such that uponselective de-energization of all of said plurality of valves by saidfield control source the quantity of flow through said plurality ofvalves will be in a predetermined proportion, and upon selectiveenergization of any one of said plurality of valves, the quantity offlow through said any one of said plurality of valves will be zero.

8. Means for controlling the flow of a fluid in the presence of a field,the combination comprising: a plurality of valves through which a fluidflows at constant pressure disposed in substantially parallelrelationship, each of said plurality of valves being insulated one fromanother by electrical insulating means and comprising:

(a) a first electrically conducting plate of length L,

width W, uniformly spaced a distance D and disposed parallel to;

(b) a second electrically conducting plate of length L, width W, andconnected to a field control source by circuit means so as to establishthe field across said plurality of valves such that upon selectivede-energization of all of `said plurality of valves by said fieldcontrol source the quantity of flow through said plurality of valveswill be in a predetermined proportion, and upon selective energizationof any one of said plurality of valves, the quantity of ow through saidany one of said plurality of -valves Will be zero.

14 Kadosch et al. 137-815 XR Crowell 137-251 Gross 137-251 Brooks137-815 Mayer 137-815 XR Bjornsen 137-815 SAMUEL SCOTT, PrimaryExaminer.

